Shamus Young has posted his proposal for an interesting Learning Mechanic at Twenty Sided. Here’s how he describes the goal of the mechanic:
Most gameplay mechanics are set up so that characters learn and grow from success. The more success, the more XP. I wanted a mechanic that would simulate an activity that was inherently driven by trial-and-error, and where (this is the important part) the character got gradually better at the activity as time went on. Learning would be fast at first, but progress would be slow. Later on, learning would slower, but success would be more frequent.
He recommends the mechanic for tasks like translating a tome written in an archaic language; finding the cure for a zombie plague; breeding animals; and the like.
Here’s how he describes the mechanic:
The player writes down all the numbers from 1 to 20 on a notecard. Every time they roll a number, that number will be crossed out on the card. If they roll a 15, then they cross out 15.
Each attempt needs to simulate a stretch of in-game time. Hours of labwork, meditation, tinkering, writing on the chalkboard, or whatever is required.
When they make an attempt, they roll the d20. If the resulting number is already crossed out, then the action was a success and they get their reward. If not, they still get to cross out the number they rolled, which will improve their chances next time around. Using a d20, they have no chance of success on their first attempt, and a 5% chance on their next attempt. Every failure improves their chances by 5%, and every success moves them closer to their goal. You decide ahead of time how many successes it will take to reach their overall goal. (For our game, I had the book broken into 13 sections. So the character finished the translation after 13 successes.)
I like the basic concept of this mechanic a lot. It’s similar to a complex skill check, but offers the specific benefits Shamus describes: At first, learning happens fast but progress is slow. Later, learning is slow but progress is fast.
STREAMLINING THE MECHANIC
The idea of keeping a notecard and crossing off number is a nifty gimmick, but if you want to streamline things then you can simplify this mechanic:
Roll 1d20. If the result is equal to or lower than the number of failed attempts you’ve made, you score a success. When you achieve the requisite number of successes, you succeed at the task.
I recommend checking out Shamus’ article directly, as he includes a probability chart useful for determining how many successes a task should require.
It should be noted that, by default, the problems handled by this mechanic are always soluble — given enough time, you will eventually solve them. There is no possiblity of absolute failure. In addition, the mechanic doesn’t account for skill. For some problems these may be seen as features. For other problems they’re bugs. Let’s take a look at how the mechanic might be made more flexible and robust.
EXTENDING THE MECHANIC
PROGRESSIVE SUCCESS: Each success can yield additional information or some other tangible benefit. (A cure that works against the bite of a specific zombie; several pages of translated text; a slightly improved animal.) The mechanic is specifically designed to model tasks which don’t feature all-or-nothing successes.
ROADBLOCK: After a certain number of successes, progress in the task may only be possible when some other prerequisite is met (additional biological samples, a different type of natural resource, etc.). In many cases, the nature of the roadblock may not be known until the roadblock is reached.
VARIABLE DIE TYPES: For tasks of greater or lesser difficulty, you could vary the die type. (With a 1d4 you learn everything about the project rapidly and then gather successes rapidly. On the other hand, with a 1d100 your learning curve takes considerably longer.)
INTRACTABLE PROBLEMS: For problems that could prove intractable for a character, simply set the maximum number of possible attempts. If the character has not achieved success after X attempts, then they’ve exhausted their insight into the problem. (Having multiple people working on a problem like this is useful not only because it speeds up resolution, but also because it gives greater insight into the problem — as represented by more potential checks.)
FACTORING SKILL, METHOD 1: You can factor the character’s skill into the attempt by limiting the number of possible attempts based on their skill. In D&D, off-the-cuff, I’d recommend something along the lines of 10 + skill modifier attempts.
FACTORING SKILL, METHOD 2: You can also make character skill a factor by simply setting a minimum skill requirement. A particular problem, for example, might require a minimum Knowledge (history) bonus of +10. (The drawback of this method is that it still doesn’t allow for any variation in completion time based on character skill. A character with a +10 bonus is just as capable of solving the problem as a character with a +50 bonus.)
FACTORING SKILL, METHOD 3: Set a DC for the task. Each d20 roll becomes an actual skill check. If the character succeeds on the check, the roll counts double. In other words, depending on the die roll, it either counts as two successes or as two failed attempts. (If you’re combining this method with an intractable problem, however, each die roll still only counts as one attempt against the maximum number of possible attempts.)
DISCLAIMER
I’m just spitballing some ideas here. I have not actually run any kind of mathematical analysis on this mechanic (although, as I noted, Shamus Young did provide useful charts for the core mechanic).
ARCHIVED HALOSCAN COMMENTS
Justin Alexander
Oh! Good thoughts! I’d probably go with the second option: 10 + bonus from all applicable skills.
Here’s what I’d probably go with: You get a base of 10 + modifier checks with the primary skill. Then you can make an additional number of checks equal to your ranks in a secondary skill. (And in some cases you can choose which skill is primary and which is secondary, presumably based which has the higher bonus.)
My primary reason for specifying ranks only for the secondary skill (instead of total modifier) is to avoid double-dipping your ability modifiers. It also inherently requires you to be trained for what is, in essence, a skill synergy.
Thursday, March 12, 2009, 2:50:37 PM
Skeolan
I. REALLY. like this mechanic. Thanks for passing it along.
I am gratified that I started thinking along the lines of “Factoring Skill, Method 1” before I’d read that far.
What about tasks which have more than one possible skill application – Arcana or Heal in solving a magical ailment, for instance? Should players be allowed to use the better of two applicable skills to determine their number of allowed attempts?
Should a character with +5 in both applicable skills get to make 30 attempts? Or perhaps (10 + 5Arc + 5Heal) 20?
Thursday, March 12, 2009, 1:41:45 PM
Using a BRP style skill system you could do the following: Roll to see if you succeed in doing something “usefull”. If not, nothing happens, if so then roll for success or failure in the suggested system.
e.g. Character with a 55% research skill.
Attempt 1, rolls 42. Something useful ! Ok roll D20 vs current DC of 3, gets 14 so no success but the DC goes up 1 to 4.
Attempt 2, rolls 67, no useful outcome. DC remains at 4.
Attempt 3, rolls 12, another useful result. D20 gives 2, a success vs DC4. 1 success on the board and DC remains at 4.
and so on…
An interesting thing about this is that it can model team attempts, with a group DC and success count at the heart of the work. Members could choose between following their own line of enquiry (skill check then DC check) or helping someone else with theirs (roll % success to improve that persons DC for one roll).
Just thinking about the team idea some more. Assume three different things need to be discovered before a fourth ultimate thing represents the success. Then the characters choose which of the three base things they work on to begin with. All characters working on a research path roll for skill success simultaneously. No successes = no useful outcome, try again later. Otherwise there is one D20 roll with a bonus of # of succeeding characters – 1 to the DC, so if 3 characters succeed the DC would go from 4 to 6 (4 + 3 -1).
You could perhaps factor in skill by using it to set how long a period each attempt represents.
Another way you could do this is as follows:
You make skill checks (using whatever skills, modifiers, and bonii are appropriate) against a DC that starts at X. If you fail a check by more than 10 points (or 20, or whatever number you like), then your check was a complete failure and accomplishes nothing. If you fail by 10 or less, you reduce the DC for all subsequent rolls by 1. If you beat the DC, you gain a success. Not sure if there should be a bonus for beating the DC by more than 10.
Alternately, along the same lines, you could have two DCs, call them the Progress DC and the Learning DC. The progress DC starts out at X, the Learning DC at X-20. Then if you fail the Learning DC nothing is gained, if you beat the Learning DC but not the Progress DC the Progress DC goes down by 1 (while the Learning DC doesn’t change), and if you beat the Progress DC you get a success.
What I like about this system is that it takes skill into account in a way that feels realistic for this kind of research task. If you already have extensive training or lots of reference materials and other useful equipment, you don’t need to learn much and can quickly make progress towards the goal. If you only have a basic competency or are working with very limited resources, you need a lot of work and experimentation but will eventually start making progress. And then if you’re completely ignorant, you can’t get anywhere at all because you don’t have the fundamentals to build upon.
As a final thought, it occurs to me that rather than lowering the DC, it might be better to apply a bonus equal to the number of partial failures to the roll. Same effect mechanically, but might feel a little closer to the desired effect.
I really love this mechanic and have started using it librally in my campaigns.
I’ve developed my own variant for team research attempts:
I set the number of steps to the problem (5 for a trivial problems, 20 for standard problems and 100 for either very complex/intractable problems or issues that are vast- these can sometimes break down into smaller research problems of their own) and then roll between 20-30% of the rolls, depending on the knowledge that the players already have of the issue.
I let the players make a number of attempts equal to their intelligence modifier, and at least one per player. I set a DC for the checks (usually 15) and then award rolls based on the successes of the research. Even if a player fails the DC, they get to make one roll (a rounded up d10/2 for trivial research, a d20 for standard problems, and a d100 for the complex issues). On a success, they get an additional roll. For every five points that the result rolled exceeds the check, I grant an additional roll- I find this is a good way that skill can be integrated into the mechanic while still allowing for successes from unskilled researchers, or failures from skilled ones.
Exactly as described, I then either cross off the result, or impart some new knowledge on the type of question/problem researched. With very complex problems, this might also be insights as to how they might be able to break down the problem further.
This is extremely old, but I’ve come up with an idea for factoring skill into it, although it only works in 5e.
Basically, create a Knowledge number which increases by 1 whenever you fail. This is not a stat, and just simplifies it to “Roll 1d20. If it’s less than your Knowledge, you succeed. Otherwise, you fail and add 1 to your Knowledge.”
But Knowledge doesn’t have to start at 0. I would start it at your skill modifier – some difficulty value. For example, a trained level 1 wizard (INT 16, proficient) would start at 5-5=0 for a difficulty 5 Arcana research check. A level 20 wizard (INT 20, proficient) would start at 11-5=6. And an untrained barbarian (INT 8, not proficient) would start at -1-5=-6.